Method and apparatus for delivering a predetermined volume of a liquid

ABSTRACT

The present invention resides in a method and apparatus suitable for laboratory or like use for transferring from one container a measured quantity of a liquid into a second container, this being accomplished by establishing a pressure difference preferably by suction applied temporarily to the second container, the first container having in it a dip pipe extending down to a selected level and leading into the second container through a stopper.

United States Patent 1191 Engelbrecht May 21', 1974 [54] METHOD AND APPARATUS FOR 978,667 12/1910 Sicka 259/010. 17

DELIVERING A PREDETERMINED agi g? 3132; VOLUME OF A LIQUID 2:724:535 11/1955 [76] Inventor: Eduard Engelbrecht, Route de 9 2/1 9 Savemy 83, 1290 Geneva, 3,725,170 ll/I955 Switzerland 3,175,732 3/1965 22 F] 8 R26,529 3/1969 1 1971 FOREIGN PATENTS OR APPLICATIONS [2]] Appl' @649 917,763 1/1947 France 141/35 Related US. Application Data [63] Continuation-impart of Ser. No. 153,055, June 14, U Examiner-Wayne Morse, 1971, which is a continuation of Ser. No. 844,088, Attorney, g or ne & ol July 23, 1969, abandoned. 52 U.S. c1 141/7, 141/35, 141/59, [57] T A 4 93 1 230 222/464 The present invention resldes in a method and appara- 5 Int. (3| 5 3/30, 7 5 5 B651, 3/14 tus suitable for laboratory or like use for transferring 5s Field-oi Search 141/7, 8, 59, 285, 230,- from one Container 8 measured quantity of a liquid 4 3 5 36, 74 75 98 222/373, into a second container, this being accomplished by 4 259/016. 7 I establishing a pressure difference preferably by suction applied temporarily to thevsecond container, the [56] References Cited first container having in it a dip pipe extending down UNITED STATES PATENTS to a selected level and leading into the second container through a stopper. 3,580,299 5/1971 Alkalay 141/59 3,683,978 8/1972 Jones 141/285 13 Claims,:8 Drawing Figures 1 I E I 1 48 g I i 1 1 I I l I I I I l I 1 z i r E 2 r t 36 34 J52 x50v PATENTEDHAY 21 1974 SHEET 1 0F 4 FIG. 75.

INVENTOR.

Mai 1 ATTORNEY v PATENTEUNAY 2 1 m4 SHET2UF4 FIG. 2

INVENTOR- Y EDWARD ENGELBRECHT BY 77% r 7 ATTORNEYS METHOD AND APPARATUS FOR DELIVERING A PREDETERMINED VOLUME OF A LIQUID This application is a continuation-in-part application of my previous application Ser. No. 153,055, filed June 14, 1971, which is a continuation of my application Ser. No. 844,088, filed July 23, 1969, now abandoned.

The present invention relates to an apparatus for deliverying a predetermined volume of a liquid from one container into another. Especially in research and technical laboratories, it is often required to have quick access to accurate dosages and it is the primary aim of this invention to supply that need; the invention also provides for adjustability of the measured volume, and for a visible operation in which measurement into an ordinary test tube can be achieved, and if it be required, a reaction can be visually observed during the measured delivery.

Accordingly to one aspect of the invention it resides in apparatus for delivering a predetermined volume of liquid from a first container into a further container, including means whereby the pressure in the further container is reduced relatively to that in the first container, and a pipe extends from an open end which is at a determined level in the first container which level is the lower level of liquid therein from below which level no further liquid-can be delivered into the further container, the said pipe extending into the further container through a stopper which is suchas to seal the top of the second container when the latter is applied thereto.

Accordingly to another aspect of the invention it resides in a. method and apparatus by which a predetermined volume of liquid is geometrically diluted. The apparatus consists of a series of tubes or pipes insertable into a series of at least three containers, such as test tubes, the first container containing a predetermined volume of liquid to be diluted, the remaining containers being charged with a predetermined volume of diluent by means herafter described. A first leg of a U-shaped tubular pipe is adapted to extend into a first container and its open end therein determining the lowest level to which liquid can be withdrawn from the first container, a second leg of the U-shaped tubular pipe is adapted to extend into a second container, positioned adjacent to the first container, through a stopper closing the mouth of thesecond container, means are attached to the stopper for evacuating the second container thereby withdrawing the liquid in the first container extending above the open end of the pipe therein and mixing it with the'diluent in the second container.

A second pipe is adapted to extend into a third container, adjacent to the container into which the second leg of the U-shaped pipe extend, which adds a predetermined volume of diluent to this container. Means are provided for moving the series of containers relatively to the pipes so that each of the containers may be operatively positioned with respect to the pipes whereby diluent may be added to the second container in the series and a transfer of a predetermined quantity of liquid to be diluted made between the first and second containers, and so on throughout the series. The continuation of this procedure throughout the series results in progressively diluting the starting liquid geometrically.

The invention also includes minor details which are hereafter described and which are defined by the claims In the first example a depression is created by means (not shown) connected to the tube 1 passing through a stopper 2, of rubber-for example, which is held pressed during used against the rim of a test tube 3. Because of the depression created, liquid 4 contained in a second test tube 5 is sucked up through the stopper 2, and thus flows into the test tube 3. The tube 7 is slightly curved so as to be tangentially'directed at its outlet, thus promoting turbulence and the mixture of the transferred liquid 4 with liquid already present in the test tube. The pipe 6 can be of flexible material; its riser or upward leg is a rigid length of pipe 8 constituting a riser supported within the test tube 5, the intake end 9 of pipe 8, being turned upward so that only the liquid above the level of its open end at 10 is abstracted. When the meniscus of the liquid 4 drops to the level of the open end 10, the liquid present in the U-shaped tube 8, 6, 7, is allsucked into the test tube 3. If a further measured dilution be required, the apparatus is shifted so that the tube 8 is within the test tube 3, and the tube 7 delivers into testtube 3, the stopper 2 having been correspondingly shifted to test tube 3'.

The test tubes, used at 5 will be such that the volume of remaining liquid 4 is predetermined; it is therefore preferable to use test tubes of plastic material obtained by molding, and therefore identical configuration.

It is possible to provide for a selection of the quanity of liquid 4 remaining in the test tube 5, and in FIGS. 1A and 1B there are shown two ways of allowing this selection.

The first consists in using a support 11 of wire or like structure formed as a U, the base of which rests on the bottom of the test tube 5 and the limbs 12 of which ensure centering and location in the test tube. The limbs of the U structure are connected by two pieces 13 and 14 in which slidably fits the pipe 8, the lower tip 9 of which is seen in FIG. 1A from the front. A screw 15 allows the positioning of the pipe 8 relatively to the support 11, at a height which can be marked on a graduated scale not represented. The limbs 11 may hang on the rim of the test tube 5 by their hooked ends, or the bottom bend of the U may rest on the bottom of the test 2E; is very similar to the example of FIG. 1. The

purpose of the method and apparatus illustrated by this example is to produce a geometrically diluted liquid. A series of pipes, generally designated 40, 42, 44 and 46, are carried by a support, generally designated 48, and are extendable into containers 50, 52, 54 and 56, 58 and 60. The pipes 40 and 42 are the legs of a generally U shaped tubula r pipe, as 'sfiifi' FIG. 2. The containers may be of any convenient form but are here illustrated as test tubes mounted in a holder 70 and movable stepwise by means of a pusher 72 which may be of any conventional form. Of course, the pipes and associated supports are movable up and down to allow the insertion of the pipes into successive ones of the test tubes. A predetermined volume of the fluid to be diluted is first added to container 50, and a predetermined volume of the diluent is added to container 52, as hereinafter described. Container 52, which is hermetically sealed by means of stopper 74, is then evacuated through pipe 44 by evacuation means not shown. The liquid to be diluted, in container 50, which is above the open end 76 of pipe 40 is then carried by means of the pressure difference between containers 50 and 52 through interconnecting pipes 40 and 42 into container 52. The open end 76 of pipe 40 is faced upwardly as previously described with respect to the first example. Because of the slightly bent end 78 of pipe 42 the liquid to be diluted passing therethrough is throughly mixed with the predetermined diluent in container 52. Pipe 46, which is shown extending into container 54, adds a predetermined amount of diluent to container 54 which afterwards is mixed with a predetermined quantity of the liquid contained in container 52 to further dilute the liquid to be diluted. This procedure is continued by a stepped movement of the containers relative to the series of pipes, as seen by the direction arrow in FIG. 2, so that pipe 40 is extended into container 52','pipes 42 and 44 are extended into container 54, and pipe 46 is extended into container 56. Continued stepped movement of the containers relative to the series of pipes will result in a geometrically diluted liquid which may be utilized effectively in an automatic machine for qualitative and quantitative analysis. What is claimed is:

' 1. A method of dividing a predetermined quantity of a liquid present in a first container into two predetermined parts one of which remains in said first container and the other of which is delivered to a second container which comprises charging a first container with a predetermined volume of a liquid to be distributed, inserting into the first container a first leg of a generally U-shaped tubular pipe so that the open end of the first leg faces upward and is located at a predetermined distance from the bottom of the first container thus establishing a known quantity of liquid above the open end, inserting the second leg of the U-shaped pipe into a second container, creating a pressure differential between the containers such that the first container is at a higher pressure than the second so that said known quantity of liquid above the open end of said first leg is moved through the U-shaped pipe to said second container, said known quantity of liquid above the open end of said first leg being caused first to move downwardly through the leg of said U-shaped pipe and then to move upwardly through said leg the upwardly facing open end of said first leg limiting inaccuracy of measurement I dl'fimrmrm delivering a predetermined volume of liquid from a first container to a second container comprising at least a first and second container, means operable to divide the predetermined quantity of the liquid contained in said first container into two predetermined quantities and for transferring one of said predetermined quantities of said liquid into said second container, said means being actuated by a reduction of the pressure in said second container relative to that in said first container and consisting of a first pipe extending into' said first container, the end of said pipe being turned upwardly with the open upwardly facing-end of said first pipe within said first container detennining the lowest level to which liquid can be withdrawn from said first container and limiting inaccuracy of measurement due .to meniscus deformation when the liquid reaches said lowest level, a second pipe extending into said second container through a stopper adapted to seal the opening of said second container when applied thereto, third pipe means connectingsaid first pipe to said second pipe, and means provided in said stopper through which suction can be applied to said second container when said second container has beeen sealed by application of said stopper thereto.

5. A method of geometrically diluting a liquid which comprises charging a first container of a series of at least three containers with a predetermined volume of liquid to be diluted geometrically, charging the remaining containers of the series with a predetermined volume of diluent, inserting a generally U-shaped tubular pipe between the first and second containers so that the open end of the tubular pipe in the first container faces upwardly and is at a predetermined distance from the bottom of the container thereby establishing a known quantity of of liquid to be diluted above the open end, creating a pressure differential between the first and second containers such that the first container is at a higher pressure than the second, moving the known, quantity of liquid to be diluted above the open end of the tubular pipe in the first container through the U- shaped tubular pipe into the second container by means of the pressure differential, mixing the liquid to be diluted which has been moved into the second container with thediluent in the second container, withdrawing the legs of the U-shaped tubular pipe from the first and second containers, then inserting the U-' shaped pipe between the second and third containers so that the open end of the tubular pipe in the second container is at a predetermined distance from the bottom of the container and faces upwardly thereby establishing a known quantity of liquid to be further diluted above the open end thereof, creating a pressure differential between the second and third containers such that the second container is at a higher pressure than the third, moving the known quantity of liquid to be further diluted above the end of the tubular pipe in the second container through the U-shaped tubular pipe into the third container by means of the pressure differential, and mixing the liquid to be further diluted which has been moved into the third container with the diluent in the third container.

' 6. The method as claimed in claim 5 wherein the steps of creating pressure differentials between containers comprises evacuating air from the container which is to be at the lower pressure.

7. Themethod as claimed in claim 5 wherein the mixing steps comprise directing the fluid issuing from the U-shaped pipe against the side of the container to induce a rotary motion in said fluid and diluent whereby the fluid is mixed with the diluent in the container.

8. The method as claimed in claim 5 wherein the steps of moving the liquid through the U-shaped pipe comprise first moving the liquid downwardly through the open end of the pipe and then upwardly through the pipe by providing the pipe with a hook at its open end so that its open end is turned upwardly.

9. Apparatus for geometrically diluting a liquid which comprises:

a. a series of at least three containers, the first of said containers containing a predetermined volume of liquid to be diluted,

b. a generally U-shaped tubular pipe to interconnect two adjacent containers in said series, the first leg of said pipe extending into a first container with the open end of said leg facing upwardly and determining the lowest level to which liquid can be with drawn from the container and limiting inaccuracy of measurement due to meniscus deformation when the liquid reaches said lowest leveL-the second leg of said pipe extending into a second container adjacent to the first container,

0. means for adding a predetermined volume of diluent to a third container adjacent to the container in saidseries into which the second leg of said U- shaped pipe extends, and t d. means for creating a pressure differential between the containers into which the legs of said U-shaped pipe extend, the container into which the first leg extends being at a higher pressure than the container into which the second leg extends thereby causing the fluid above the open end of the first leg of said U-shaped pipe to be transferred through said pipe into the interconnected container to be mixed therein with the diluent present,

whereby a predetermined volume of diluent may be added to each container in the series and the liquid to be diluted may be geometrically diluted by sequentially transferring a predetermined amount of the fluid contained in one container to another in the series.

10. The apparatus as defined in claim 9 wherein the means for creating a pressure differential comprises means for hermetically sealing the container into which the second leg of said U-shaped pipe extends, and means for evacuating air from the container into which the second leg of said U-shaped pipe extends while said container is hermetically sealed.

11. The apparatus as defined in claim 10 wherein the hermetically sealing means comprises a stopper through which the second leg of said U-shaped pipe extends and which is adapted to seal the mouth of the container to which it is applied.

12. The apparatus as defined in claim 9 wherein the diluent adding means includes a tubular pipe'adjacent to the second leg of said U-shaped pipe and adapted to extend into the container adjacent to the container into which said second leg is adapted to extend and through which the diluent passes into the container.

13. The apparatus as defined in claim 9'wherein the first leg of said U-shaped tubular pipe is hooked near its open end so that its open end faces upwardly and the liquid to be transferred first passes downwardly and then upwardly in said leg, and the second leg of said U- shaped tubular pipe is slightly bent at its end to direct the liquid issuing therefrom against the side of the container. 

1. A method of dividing a predetermined quantity of a liquid present in a first container into two predetermined parts one of which remains in said first container and the other of which is delivered to a second container which comprises charging a first container with a predetermined volume of a liquid to be distributed, inserting into the first container a first leg of a generally U-shaped tubular pipe so that the open end of the first leg faces upward and is located at a predetermined distance from the bottom of the first container thus establishing a known quantity of liquid above the open end, inserting the second leg of the U-shaped pipe into a second container, creating a pressure differential between the containers such that the first container is at a higher pressure than the second so that said known quantity of liquid above the open end of said first leg is moved through the U-shaped pipe to said second container, said known quantity of liquid above the open end of said first leg being caused first to move downwardly through the leg of said U-shaped pipe and then to move upwardly through said leg the upwardly facing open end of said first leg limiting inaccuracy of measurement due to meniscus deformation when the known quantity of liquid is moved through said first leg.
 2. The method as claimed in claim 1 wherein said second container is cylindrical which comprises directing the end of the second leg of said U-shaped pipe at an angle to the axis of said container to cause liquid issuing therefrom into the second container to impinge on the wall of said container and to produce a rotary movement of any liquid in said second container.
 3. The methoD as claimed in claim 1 wherein the end of the first leg of said U-shaped pipe is hooked and the leg is inserted into the first container so that its open end is turned upwardly.
 4. Apparatus for delivering a predetermined volume of liquid from a first container to a second container comprising at least a first and second container, means operable to divide the predetermined quantity of the liquid contained in said first container into two predetermined quantities and for transferring one of said predetermined quantities of said liquid into said second container, said means being actuated by a reduction of the pressure in said second container relative to that in said first container and consisting of a first pipe extending into said first container, the end of said pipe being turned upwardly with the open upwardly facing end of said first pipe within said first container determining the lowest level to which liquid can be withdrawn from said first container and limiting inaccuracy of measurement due to meniscus deformation when the liquid reaches said lowest level, a second pipe extending into said second container through a stopper adapted to seal the opening of said second container when applied thereto, third pipe means connecting said first pipe to said second pipe, and means provided in said stopper through which suction can be applied to said second container when said second container has beeen sealed by application of said stopper thereto.
 5. A method of geometrically diluting a liquid which comprises charging a first container of a series of at least three containers with a predetermined volume of liquid to be diluted geometrically, charging the remaining containers of the series with a predetermined volume of diluent, inserting a generally U-shaped tubular pipe between the first and second containers so that the open end of the tubular pipe in the first container faces upwardly and is at a predetermined distance from the bottom of the container thereby establishing a known quantity of of liquid to be diluted above the open end, creating a pressure differential between the first and second containers such that the first container is at a higher pressure than the second, moving the known quantity of liquid to be diluted above the open end of the tubular pipe in the first container through the U-shaped tubular pipe into the second container by means of the pressure differential, mixing the liquid to be diluted which has been moved into the second container with the diluent in the second container, withdrawing the legs of the U-shaped tubular pipe from the first and second containers, then inserting the U-shaped pipe between the second and third containers so that the open end of the tubular pipe in the second container is at a predetermined distance from the bottom of the container and faces upwardly thereby establishing a known quantity of liquid to be further diluted above the open end thereof, creating a pressure differential between the second and third containers such that the second container is at a higher pressure than the third, moving the known quantity of liquid to be further diluted above the end of the tubular pipe in the second container through the U-shaped tubular pipe into the third container by means of the pressure differential, and mixing the liquid to be further diluted which has been moved into the third container with the diluent in the third container.
 6. The method as claimed in claim 5 wherein the steps of creating pressure differentials between containers comprises evacuating air from the container which is to be at the lower pressure.
 7. The method as claimed in claim 5 wherein the mixing steps comprise directing the fluid issuing from the U-shaped pipe against the side of the container to induce a rotary motion in said fluid and diluent whereby the fluid is mixed with the diluent in the container.
 8. The method as claimed in claim 5 wherein the steps of moving the liquid through the U-shaped pipe compRise first moving the liquid downwardly through the open end of the pipe and then upwardly through the pipe by providing the pipe with a hook at its open end so that its open end is turned upwardly.
 9. Apparatus for geometrically diluting a liquid which comprises: a. a series of at least three containers, the first of said containers containing a predetermined volume of liquid to be diluted, b. a generally U-shaped tubular pipe to interconnect two adjacent containers in said series, the first leg of said pipe extending into a first container with the open end of said leg facing upwardly and determining the lowest level to which liquid can be withdrawn from the container and limiting inaccuracy of measurement due to meniscus deformation when the liquid reaches said lowest level, the second leg of said pipe extending into a second container adjacent to the first container, c. means for adding a predetermined volume of diluent to a third container adjacent to the container in said series into which the second leg of said U-shaped pipe extends, and d. means for creating a pressure differential between the containers into which the legs of said U-shaped pipe extend, the container into which the first leg extends being at a higher pressure than the container into which the second leg extends thereby causing the fluid above the open end of the first leg of said U-shaped pipe to be transferred through said pipe into the interconnected container to be mixed therein with the diluent present, whereby a predetermined volume of diluent may be added to each container in the series and the liquid to be diluted may be geometrically diluted by sequentially transferring a predetermined amount of the fluid contained in one container to another in the series.
 10. The apparatus as defined in claim 9 wherein the means for creating a pressure differential comprises means for hermetically sealing the container into which the second leg of said U-shaped pipe extends, and means for evacuating air from the container into which the second leg of said U-shaped pipe extends while said container is hermetically sealed.
 11. The apparatus as defined in claim 10 wherein the hermetically sealing means comprises a stopper through which the second leg of said U-shaped pipe extends and which is adapted to seal the mouth of the container to which it is applied.
 12. The apparatus as defined in claim 9 wherein the diluent adding means includes a tubular pipe adjacent to the second leg of said U-shaped pipe and adapted to extend into the container adjacent to the container into which said second leg is adapted to extend and through which the diluent passes into the container.
 13. The apparatus as defined in claim 9 wherein the first leg of said U-shaped tubular pipe is hooked near its open end so that its open end faces upwardly and the liquid to be transferred first passes downwardly and then upwardly in said leg, and the second leg of said U-shaped tubular pipe is slightly bent at its end to direct the liquid issuing therefrom against the side of the container. 